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authorJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2010-12-06 16:29:22 -0800
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2011-01-11 14:31:07 -0500
commitb5eafe924bb054d7c56e6ebd18106352e8a3f916 (patch)
treeb7e88c3259df6f5a57d7b04225a053ac435c1a9d
parent8d3eaea24609c7cd6fb0e6471f46a52f9e5d0202 (diff)
downloadlinux-linaro-android-b5eafe924bb054d7c56e6ebd18106352e8a3f916.tar.gz
xen: move p2m handling to separate file
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
-rw-r--r--arch/x86/xen/Makefile3
-rw-r--r--arch/x86/xen/mmu.c365
-rw-r--r--arch/x86/xen/p2m.c376
3 files changed, 378 insertions, 366 deletions
diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
index 77938515891..17c565de3d6 100644
--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -12,7 +12,8 @@ CFLAGS_mmu.o := $(nostackp)
obj-y := enlighten.o setup.o multicalls.o mmu.o irq.o \
time.o xen-asm.o xen-asm_$(BITS).o \
- grant-table.o suspend.o platform-pci-unplug.o
+ grant-table.o suspend.o platform-pci-unplug.o \
+ p2m.o
obj-$(CONFIG_SMP) += smp.o
obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= spinlock.o
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 44924e551fd..7575e55cd52 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -173,371 +173,6 @@ DEFINE_PER_CPU(unsigned long, xen_current_cr3); /* actual vcpu cr3 */
*/
#define USER_LIMIT ((STACK_TOP_MAX + PGDIR_SIZE - 1) & PGDIR_MASK)
-/*
- * Xen leaves the responsibility for maintaining p2m mappings to the
- * guests themselves, but it must also access and update the p2m array
- * during suspend/resume when all the pages are reallocated.
- *
- * The p2m table is logically a flat array, but we implement it as a
- * three-level tree to allow the address space to be sparse.
- *
- * Xen
- * |
- * p2m_top p2m_top_mfn
- * / \ / \
- * p2m_mid p2m_mid p2m_mid_mfn p2m_mid_mfn
- * / \ / \ / /
- * p2m p2m p2m p2m p2m p2m p2m ...
- *
- * The p2m_mid_mfn pages are mapped by p2m_top_mfn_p.
- *
- * The p2m_top and p2m_top_mfn levels are limited to 1 page, so the
- * maximum representable pseudo-physical address space is:
- * P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE pages
- *
- * P2M_PER_PAGE depends on the architecture, as a mfn is always
- * unsigned long (8 bytes on 64-bit, 4 bytes on 32), leading to
- * 512 and 1024 entries respectively.
- */
-
-unsigned long xen_max_p2m_pfn __read_mostly;
-
-#define P2M_PER_PAGE (PAGE_SIZE / sizeof(unsigned long))
-#define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *))
-#define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **))
-
-#define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE)
-
-/* Placeholders for holes in the address space */
-static RESERVE_BRK_ARRAY(unsigned long, p2m_missing, P2M_PER_PAGE);
-static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_missing, P2M_MID_PER_PAGE);
-static RESERVE_BRK_ARRAY(unsigned long, p2m_mid_missing_mfn, P2M_MID_PER_PAGE);
-
-static RESERVE_BRK_ARRAY(unsigned long **, p2m_top, P2M_TOP_PER_PAGE);
-static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn, P2M_TOP_PER_PAGE);
-static RESERVE_BRK_ARRAY(unsigned long *, p2m_top_mfn_p, P2M_TOP_PER_PAGE);
-
-RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));
-RESERVE_BRK(p2m_mid_mfn, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));
-
-static inline unsigned p2m_top_index(unsigned long pfn)
-{
- BUG_ON(pfn >= MAX_P2M_PFN);
- return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE);
-}
-
-static inline unsigned p2m_mid_index(unsigned long pfn)
-{
- return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE;
-}
-
-static inline unsigned p2m_index(unsigned long pfn)
-{
- return pfn % P2M_PER_PAGE;
-}
-
-static void p2m_top_init(unsigned long ***top)
-{
- unsigned i;
-
- for (i = 0; i < P2M_TOP_PER_PAGE; i++)
- top[i] = p2m_mid_missing;
-}
-
-static void p2m_top_mfn_init(unsigned long *top)
-{
- unsigned i;
-
- for (i = 0; i < P2M_TOP_PER_PAGE; i++)
- top[i] = virt_to_mfn(p2m_mid_missing_mfn);
-}
-
-static void p2m_top_mfn_p_init(unsigned long **top)
-{
- unsigned i;
-
- for (i = 0; i < P2M_TOP_PER_PAGE; i++)
- top[i] = p2m_mid_missing_mfn;
-}
-
-static void p2m_mid_init(unsigned long **mid)
-{
- unsigned i;
-
- for (i = 0; i < P2M_MID_PER_PAGE; i++)
- mid[i] = p2m_missing;
-}
-
-static void p2m_mid_mfn_init(unsigned long *mid)
-{
- unsigned i;
-
- for (i = 0; i < P2M_MID_PER_PAGE; i++)
- mid[i] = virt_to_mfn(p2m_missing);
-}
-
-static void p2m_init(unsigned long *p2m)
-{
- unsigned i;
-
- for (i = 0; i < P2M_MID_PER_PAGE; i++)
- p2m[i] = INVALID_P2M_ENTRY;
-}
-
-/*
- * Build the parallel p2m_top_mfn and p2m_mid_mfn structures
- *
- * This is called both at boot time, and after resuming from suspend:
- * - At boot time we're called very early, and must use extend_brk()
- * to allocate memory.
- *
- * - After resume we're called from within stop_machine, but the mfn
- * tree should alreay be completely allocated.
- */
-void xen_build_mfn_list_list(void)
-{
- unsigned long pfn;
-
- /* Pre-initialize p2m_top_mfn to be completely missing */
- if (p2m_top_mfn == NULL) {
- p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE);
- p2m_mid_mfn_init(p2m_mid_missing_mfn);
-
- p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);
- p2m_top_mfn_p_init(p2m_top_mfn_p);
-
- p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE);
- p2m_top_mfn_init(p2m_top_mfn);
- } else {
- /* Reinitialise, mfn's all change after migration */
- p2m_mid_mfn_init(p2m_mid_missing_mfn);
- }
-
- for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += P2M_PER_PAGE) {
- unsigned topidx = p2m_top_index(pfn);
- unsigned mididx = p2m_mid_index(pfn);
- unsigned long **mid;
- unsigned long *mid_mfn_p;
-
- mid = p2m_top[topidx];
- mid_mfn_p = p2m_top_mfn_p[topidx];
-
- /* Don't bother allocating any mfn mid levels if
- * they're just missing, just update the stored mfn,
- * since all could have changed over a migrate.
- */
- if (mid == p2m_mid_missing) {
- BUG_ON(mididx);
- BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
- p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn);
- pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE;
- continue;
- }
-
- if (mid_mfn_p == p2m_mid_missing_mfn) {
- /*
- * XXX boot-time only! We should never find
- * missing parts of the mfn tree after
- * runtime. extend_brk() will BUG if we call
- * it too late.
- */
- mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);
- p2m_mid_mfn_init(mid_mfn_p);
-
- p2m_top_mfn_p[topidx] = mid_mfn_p;
- }
-
- p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
- mid_mfn_p[mididx] = virt_to_mfn(mid[mididx]);
- }
-}
-
-void xen_setup_mfn_list_list(void)
-{
- BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
-
- HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
- virt_to_mfn(p2m_top_mfn);
- HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn;
-}
-
-/* Set up p2m_top to point to the domain-builder provided p2m pages */
-void __init xen_build_dynamic_phys_to_machine(void)
-{
- unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list;
- unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);
- unsigned long pfn;
-
- xen_max_p2m_pfn = max_pfn;
-
- p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE);
- p2m_init(p2m_missing);
-
- p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE);
- p2m_mid_init(p2m_mid_missing);
-
- p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE);
- p2m_top_init(p2m_top);
-
- /*
- * The domain builder gives us a pre-constructed p2m array in
- * mfn_list for all the pages initially given to us, so we just
- * need to graft that into our tree structure.
- */
- for (pfn = 0; pfn < max_pfn; pfn += P2M_PER_PAGE) {
- unsigned topidx = p2m_top_index(pfn);
- unsigned mididx = p2m_mid_index(pfn);
-
- if (p2m_top[topidx] == p2m_mid_missing) {
- unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE);
- p2m_mid_init(mid);
-
- p2m_top[topidx] = mid;
- }
-
- p2m_top[topidx][mididx] = &mfn_list[pfn];
- }
-}
-
-unsigned long get_phys_to_machine(unsigned long pfn)
-{
- unsigned topidx, mididx, idx;
-
- if (unlikely(pfn >= MAX_P2M_PFN))
- return INVALID_P2M_ENTRY;
-
- topidx = p2m_top_index(pfn);
- mididx = p2m_mid_index(pfn);
- idx = p2m_index(pfn);
-
- return p2m_top[topidx][mididx][idx];
-}
-EXPORT_SYMBOL_GPL(get_phys_to_machine);
-
-static void *alloc_p2m_page(void)
-{
- return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT);
-}
-
-static void free_p2m_page(void *p)
-{
- free_page((unsigned long)p);
-}
-
-/*
- * Fully allocate the p2m structure for a given pfn. We need to check
- * that both the top and mid levels are allocated, and make sure the
- * parallel mfn tree is kept in sync. We may race with other cpus, so
- * the new pages are installed with cmpxchg; if we lose the race then
- * simply free the page we allocated and use the one that's there.
- */
-static bool alloc_p2m(unsigned long pfn)
-{
- unsigned topidx, mididx;
- unsigned long ***top_p, **mid;
- unsigned long *top_mfn_p, *mid_mfn;
-
- topidx = p2m_top_index(pfn);
- mididx = p2m_mid_index(pfn);
-
- top_p = &p2m_top[topidx];
- mid = *top_p;
-
- if (mid == p2m_mid_missing) {
- /* Mid level is missing, allocate a new one */
- mid = alloc_p2m_page();
- if (!mid)
- return false;
-
- p2m_mid_init(mid);
-
- if (cmpxchg(top_p, p2m_mid_missing, mid) != p2m_mid_missing)
- free_p2m_page(mid);
- }
-
- top_mfn_p = &p2m_top_mfn[topidx];
- mid_mfn = p2m_top_mfn_p[topidx];
-
- BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
-
- if (mid_mfn == p2m_mid_missing_mfn) {
- /* Separately check the mid mfn level */
- unsigned long missing_mfn;
- unsigned long mid_mfn_mfn;
-
- mid_mfn = alloc_p2m_page();
- if (!mid_mfn)
- return false;
-
- p2m_mid_mfn_init(mid_mfn);
-
- missing_mfn = virt_to_mfn(p2m_mid_missing_mfn);
- mid_mfn_mfn = virt_to_mfn(mid_mfn);
- if (cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn) != missing_mfn)
- free_p2m_page(mid_mfn);
- else
- p2m_top_mfn_p[topidx] = mid_mfn;
- }
-
- if (p2m_top[topidx][mididx] == p2m_missing) {
- /* p2m leaf page is missing */
- unsigned long *p2m;
-
- p2m = alloc_p2m_page();
- if (!p2m)
- return false;
-
- p2m_init(p2m);
-
- if (cmpxchg(&mid[mididx], p2m_missing, p2m) != p2m_missing)
- free_p2m_page(p2m);
- else
- mid_mfn[mididx] = virt_to_mfn(p2m);
- }
-
- return true;
-}
-
-/* Try to install p2m mapping; fail if intermediate bits missing */
-bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
-{
- unsigned topidx, mididx, idx;
-
- if (unlikely(pfn >= MAX_P2M_PFN)) {
- BUG_ON(mfn != INVALID_P2M_ENTRY);
- return true;
- }
-
- topidx = p2m_top_index(pfn);
- mididx = p2m_mid_index(pfn);
- idx = p2m_index(pfn);
-
- if (p2m_top[topidx][mididx] == p2m_missing)
- return mfn == INVALID_P2M_ENTRY;
-
- p2m_top[topidx][mididx][idx] = mfn;
-
- return true;
-}
-
-bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
-{
- if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {
- BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
- return true;
- }
-
- if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
- if (!alloc_p2m(pfn))
- return false;
-
- if (!__set_phys_to_machine(pfn, mfn))
- return false;
- }
-
- return true;
-}
-
unsigned long arbitrary_virt_to_mfn(void *vaddr)
{
xmaddr_t maddr = arbitrary_virt_to_machine(vaddr);
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
new file mode 100644
index 00000000000..259ec3bb8b6
--- /dev/null
+++ b/arch/x86/xen/p2m.c
@@ -0,0 +1,376 @@
+/*
+ * Xen leaves the responsibility for maintaining p2m mappings to the
+ * guests themselves, but it must also access and update the p2m array
+ * during suspend/resume when all the pages are reallocated.
+ *
+ * The p2m table is logically a flat array, but we implement it as a
+ * three-level tree to allow the address space to be sparse.
+ *
+ * Xen
+ * |
+ * p2m_top p2m_top_mfn
+ * / \ / \
+ * p2m_mid p2m_mid p2m_mid_mfn p2m_mid_mfn
+ * / \ / \ / /
+ * p2m p2m p2m p2m p2m p2m p2m ...
+ *
+ * The p2m_mid_mfn pages are mapped by p2m_top_mfn_p.
+ *
+ * The p2m_top and p2m_top_mfn levels are limited to 1 page, so the
+ * maximum representable pseudo-physical address space is:
+ * P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE pages
+ *
+ * P2M_PER_PAGE depends on the architecture, as a mfn is always
+ * unsigned long (8 bytes on 64-bit, 4 bytes on 32), leading to
+ * 512 and 1024 entries respectively.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+
+#include <asm/cache.h>
+#include <asm/setup.h>
+
+#include <asm/xen/page.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+
+#include "xen-ops.h"
+
+unsigned long xen_max_p2m_pfn __read_mostly;
+
+#define P2M_PER_PAGE (PAGE_SIZE / sizeof(unsigned long))
+#define P2M_MID_PER_PAGE (PAGE_SIZE / sizeof(unsigned long *))
+#define P2M_TOP_PER_PAGE (PAGE_SIZE / sizeof(unsigned long **))
+
+#define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE)
+
+/* Placeholders for holes in the address space */
+static RESERVE_BRK_ARRAY(unsigned long, p2m_missing, P2M_PER_PAGE);
+static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_missing, P2M_MID_PER_PAGE);
+static RESERVE_BRK_ARRAY(unsigned long, p2m_mid_missing_mfn, P2M_MID_PER_PAGE);
+
+static RESERVE_BRK_ARRAY(unsigned long **, p2m_top, P2M_TOP_PER_PAGE);
+static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn, P2M_TOP_PER_PAGE);
+static RESERVE_BRK_ARRAY(unsigned long *, p2m_top_mfn_p, P2M_TOP_PER_PAGE);
+
+RESERVE_BRK(p2m_mid, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));
+RESERVE_BRK(p2m_mid_mfn, PAGE_SIZE * (MAX_DOMAIN_PAGES / (P2M_PER_PAGE * P2M_MID_PER_PAGE)));
+
+static inline unsigned p2m_top_index(unsigned long pfn)
+{
+ BUG_ON(pfn >= MAX_P2M_PFN);
+ return pfn / (P2M_MID_PER_PAGE * P2M_PER_PAGE);
+}
+
+static inline unsigned p2m_mid_index(unsigned long pfn)
+{
+ return (pfn / P2M_PER_PAGE) % P2M_MID_PER_PAGE;
+}
+
+static inline unsigned p2m_index(unsigned long pfn)
+{
+ return pfn % P2M_PER_PAGE;
+}
+
+static void p2m_top_init(unsigned long ***top)
+{
+ unsigned i;
+
+ for (i = 0; i < P2M_TOP_PER_PAGE; i++)
+ top[i] = p2m_mid_missing;
+}
+
+static void p2m_top_mfn_init(unsigned long *top)
+{
+ unsigned i;
+
+ for (i = 0; i < P2M_TOP_PER_PAGE; i++)
+ top[i] = virt_to_mfn(p2m_mid_missing_mfn);
+}
+
+static void p2m_top_mfn_p_init(unsigned long **top)
+{
+ unsigned i;
+
+ for (i = 0; i < P2M_TOP_PER_PAGE; i++)
+ top[i] = p2m_mid_missing_mfn;
+}
+
+static void p2m_mid_init(unsigned long **mid)
+{
+ unsigned i;
+
+ for (i = 0; i < P2M_MID_PER_PAGE; i++)
+ mid[i] = p2m_missing;
+}
+
+static void p2m_mid_mfn_init(unsigned long *mid)
+{
+ unsigned i;
+
+ for (i = 0; i < P2M_MID_PER_PAGE; i++)
+ mid[i] = virt_to_mfn(p2m_missing);
+}
+
+static void p2m_init(unsigned long *p2m)
+{
+ unsigned i;
+
+ for (i = 0; i < P2M_MID_PER_PAGE; i++)
+ p2m[i] = INVALID_P2M_ENTRY;
+}
+
+/*
+ * Build the parallel p2m_top_mfn and p2m_mid_mfn structures
+ *
+ * This is called both at boot time, and after resuming from suspend:
+ * - At boot time we're called very early, and must use extend_brk()
+ * to allocate memory.
+ *
+ * - After resume we're called from within stop_machine, but the mfn
+ * tree should alreay be completely allocated.
+ */
+void xen_build_mfn_list_list(void)
+{
+ unsigned long pfn;
+
+ /* Pre-initialize p2m_top_mfn to be completely missing */
+ if (p2m_top_mfn == NULL) {
+ p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ p2m_mid_mfn_init(p2m_mid_missing_mfn);
+
+ p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ p2m_top_mfn_p_init(p2m_top_mfn_p);
+
+ p2m_top_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ p2m_top_mfn_init(p2m_top_mfn);
+ } else {
+ /* Reinitialise, mfn's all change after migration */
+ p2m_mid_mfn_init(p2m_mid_missing_mfn);
+ }
+
+ for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += P2M_PER_PAGE) {
+ unsigned topidx = p2m_top_index(pfn);
+ unsigned mididx = p2m_mid_index(pfn);
+ unsigned long **mid;
+ unsigned long *mid_mfn_p;
+
+ mid = p2m_top[topidx];
+ mid_mfn_p = p2m_top_mfn_p[topidx];
+
+ /* Don't bother allocating any mfn mid levels if
+ * they're just missing, just update the stored mfn,
+ * since all could have changed over a migrate.
+ */
+ if (mid == p2m_mid_missing) {
+ BUG_ON(mididx);
+ BUG_ON(mid_mfn_p != p2m_mid_missing_mfn);
+ p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn);
+ pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE;
+ continue;
+ }
+
+ if (mid_mfn_p == p2m_mid_missing_mfn) {
+ /*
+ * XXX boot-time only! We should never find
+ * missing parts of the mfn tree after
+ * runtime. extend_brk() will BUG if we call
+ * it too late.
+ */
+ mid_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ p2m_mid_mfn_init(mid_mfn_p);
+
+ p2m_top_mfn_p[topidx] = mid_mfn_p;
+ }
+
+ p2m_top_mfn[topidx] = virt_to_mfn(mid_mfn_p);
+ mid_mfn_p[mididx] = virt_to_mfn(mid[mididx]);
+ }
+}
+
+void xen_setup_mfn_list_list(void)
+{
+ BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
+
+ HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
+ virt_to_mfn(p2m_top_mfn);
+ HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn;
+}
+
+/* Set up p2m_top to point to the domain-builder provided p2m pages */
+void __init xen_build_dynamic_phys_to_machine(void)
+{
+ unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list;
+ unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);
+ unsigned long pfn;
+
+ xen_max_p2m_pfn = max_pfn;
+
+ p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ p2m_init(p2m_missing);
+
+ p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ p2m_mid_init(p2m_mid_missing);
+
+ p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ p2m_top_init(p2m_top);
+
+ /*
+ * The domain builder gives us a pre-constructed p2m array in
+ * mfn_list for all the pages initially given to us, so we just
+ * need to graft that into our tree structure.
+ */
+ for (pfn = 0; pfn < max_pfn; pfn += P2M_PER_PAGE) {
+ unsigned topidx = p2m_top_index(pfn);
+ unsigned mididx = p2m_mid_index(pfn);
+
+ if (p2m_top[topidx] == p2m_mid_missing) {
+ unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE);
+ p2m_mid_init(mid);
+
+ p2m_top[topidx] = mid;
+ }
+
+ p2m_top[topidx][mididx] = &mfn_list[pfn];
+ }
+}
+
+unsigned long get_phys_to_machine(unsigned long pfn)
+{
+ unsigned topidx, mididx, idx;
+
+ if (unlikely(pfn >= MAX_P2M_PFN))
+ return INVALID_P2M_ENTRY;
+
+ topidx = p2m_top_index(pfn);
+ mididx = p2m_mid_index(pfn);
+ idx = p2m_index(pfn);
+
+ return p2m_top[topidx][mididx][idx];
+}
+EXPORT_SYMBOL_GPL(get_phys_to_machine);
+
+static void *alloc_p2m_page(void)
+{
+ return (void *)__get_free_page(GFP_KERNEL | __GFP_REPEAT);
+}
+
+static void free_p2m_page(void *p)
+{
+ free_page((unsigned long)p);
+}
+
+/*
+ * Fully allocate the p2m structure for a given pfn. We need to check
+ * that both the top and mid levels are allocated, and make sure the
+ * parallel mfn tree is kept in sync. We may race with other cpus, so
+ * the new pages are installed with cmpxchg; if we lose the race then
+ * simply free the page we allocated and use the one that's there.
+ */
+static bool alloc_p2m(unsigned long pfn)
+{
+ unsigned topidx, mididx;
+ unsigned long ***top_p, **mid;
+ unsigned long *top_mfn_p, *mid_mfn;
+
+ topidx = p2m_top_index(pfn);
+ mididx = p2m_mid_index(pfn);
+
+ top_p = &p2m_top[topidx];
+ mid = *top_p;
+
+ if (mid == p2m_mid_missing) {
+ /* Mid level is missing, allocate a new one */
+ mid = alloc_p2m_page();
+ if (!mid)
+ return false;
+
+ p2m_mid_init(mid);
+
+ if (cmpxchg(top_p, p2m_mid_missing, mid) != p2m_mid_missing)
+ free_p2m_page(mid);
+ }
+
+ top_mfn_p = &p2m_top_mfn[topidx];
+ mid_mfn = p2m_top_mfn_p[topidx];
+
+ BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p);
+
+ if (mid_mfn == p2m_mid_missing_mfn) {
+ /* Separately check the mid mfn level */
+ unsigned long missing_mfn;
+ unsigned long mid_mfn_mfn;
+
+ mid_mfn = alloc_p2m_page();
+ if (!mid_mfn)
+ return false;
+
+ p2m_mid_mfn_init(mid_mfn);
+
+ missing_mfn = virt_to_mfn(p2m_mid_missing_mfn);
+ mid_mfn_mfn = virt_to_mfn(mid_mfn);
+ if (cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn) != missing_mfn)
+ free_p2m_page(mid_mfn);
+ else
+ p2m_top_mfn_p[topidx] = mid_mfn;
+ }
+
+ if (p2m_top[topidx][mididx] == p2m_missing) {
+ /* p2m leaf page is missing */
+ unsigned long *p2m;
+
+ p2m = alloc_p2m_page();
+ if (!p2m)
+ return false;
+
+ p2m_init(p2m);
+
+ if (cmpxchg(&mid[mididx], p2m_missing, p2m) != p2m_missing)
+ free_p2m_page(p2m);
+ else
+ mid_mfn[mididx] = virt_to_mfn(p2m);
+ }
+
+ return true;
+}
+
+/* Try to install p2m mapping; fail if intermediate bits missing */
+bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
+{
+ unsigned topidx, mididx, idx;
+
+ if (unlikely(pfn >= MAX_P2M_PFN)) {
+ BUG_ON(mfn != INVALID_P2M_ENTRY);
+ return true;
+ }
+
+ topidx = p2m_top_index(pfn);
+ mididx = p2m_mid_index(pfn);
+ idx = p2m_index(pfn);
+
+ if (p2m_top[topidx][mididx] == p2m_missing)
+ return mfn == INVALID_P2M_ENTRY;
+
+ p2m_top[topidx][mididx][idx] = mfn;
+
+ return true;
+}
+
+bool set_phys_to_machine(unsigned long pfn, unsigned long mfn)
+{
+ if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) {
+ BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
+ return true;
+ }
+
+ if (unlikely(!__set_phys_to_machine(pfn, mfn))) {
+ if (!alloc_p2m(pfn))
+ return false;
+
+ if (!__set_phys_to_machine(pfn, mfn))
+ return false;
+ }
+
+ return true;
+}